A pilot controls an aircraft in particular with the help of a control stick that can be moved in roll and/or in pitch, i.e. from left to right and from front to rear, and vice versa.
More particularly, on a helicopter, the control sticks, referred to as “cyclic pitch control sticks” by the person skilled in the art, enable the pilot to control the cyclical variation of the pitch of the blades of the helicopter. By inclining the plane of the helicopter rotor in this way, using the control sticks, the pilot can direct the helicopter in desired manner.
In addition, most aircraft are designed to be controlled by both a pilot and a co-pilot, which requires two control sticks to be used. Naturally, both control sticks must be capable of moving together, and identically, so that either the pilot or the co-pilot is in a position to control the aircraft.
A first device is known that is provided with first and second control sticks. The sticks are interconnected by a roll interlinking shaft and by a pitch interlinking shaft serving respectively to interlink the roll movements and the pitch movements of the control sticks, the pitch interlinking shaft being secured to the structure of the aircraft via bearings.
Thus, the ends of the roll and pitch interlinking shafts are connected to the control sticks via hinges, the pitch interlinking shaft being disposed above the roll interlinking shaft.
Thus, because of said hinges, when the pilot seeks to move the first control stick from front to rear, or vice versa, the first control stick turns the pitch interlinking shaft which in turn moves the second control stick. It should be observed that this movement also has the consequence of moving the roll interlinking shaft through a considerable angle.
If the pilot moves the first control stick from left to right, and vice versa, then the first control stick moves the roll interlinking shaft transversely, thereby transferring the movement of the first control stick to the second control stick.
It is thus easily understood that it is also possible to combine both types of movement.
Although extremely effective, that device occupies a considerable amount of space. It is necessary firstly to secure the pitch interlinking shaft to the structure of the aircraft and then to “cut into” said structure so as to be able to provide the roll interlinking shaft with sufficient space to allow said roll interlinking shaft to sweep through an angle when the control sticks are moved in pitch.
Since the space available in an aircraft is very limited, the overall size of that first device is therefore undesirable.